1. Field of the Invention
The present invention concerns a color filter substrate having high visibility, a method of manufacturing such color filter substrate, a displaying device having such color filter substrate, an electro-optical device having such color filter substrate and an electronic instrument having such color filter substrate.
2. Background Information
A conventional liquid crystal display device is known to be equipped with a color filter substrate that functions both as a reflective display that uses external light and a transmissive display that uses a backlight. When such conventional liquid crystal display device functions as a reflective display, colored light is obtained when the incoming light from outside passes through coloring layers that are provided for color-display purposes. Accordingly, the display is inevitably darkened because the incoming light is partially absorbed by the coloring layers. To prevent this problem, as disclosed in Japanese Laid-open Patent Application Publication No. H11-183892, it has been known to provide in portions of the coloring layers colorless openings and reflecting films that correspond to the openings, such that part of the incoming light passes through the openings to be reflected at the reflecting films as colorless light without being absorbed by the coloring layers. By mixing the colorless light with colored light, it is possible to obtain a brighter display than the case where all of the incoming light passes through the coloring layers and becomes colored.
Electro-optical devices such as liquid crystal devices and organic EL devices that have the color display function have been known. These types of electro-optical devices internally contain a color filter substrate. The color filter substrate is formed, for instance, with R (red), G (green) and B (blue) coloring elements disposed in a predetermined arrangement on a substrate of, for example, transparent glass.
There are three known types of liquid crystal devices. The first is so-called a reflective type liquid crystal device in which external light such as the sun light or room light is reflected internally within the device such that the reflected light is displayed. The second is so-called a transmissive type liquid crystal device in which the light is emitted by a cold cathode tube, LED (light emitting diode) or other light source and passes through inside the liquid crystal device. The third is a semi-transmissive-reflective type liquid crystal device that has functions of both of the reflective and transmissive type liquid crystal devices.
In both the reflective and semi-transmissive-reflective type liquid crystal devices, when the display uses reflected light to display image, the external light passes through coloring elements of the color filter twice, which increases color absorption and reduces the display brightness. To solve this problem, a reflective type liquid crystal devices that have within the pixel area an uncolored region, in other words an exposed reflective film, is known. Japanese Laid-Open Patent Application Publication 10-186347 in FIG. 1 shows such reflective type liquid crystal device. In this liquid crystal device, the passage of bright light through the exposed region of the reflective film prevents the reduction in brightness of color display.
However, in Japanese Laid-open Patent Application No. H11-183892, in order to implement the conventional arrangement described above, parts of the coloring layers need to be formed as openings that act as non-coloring layers. In other words, the coloring layers must be formed so as to be divided into coloring components and non-coloring components. Additionally, the coloring layers are generally closely disposed next to one another. Accordingly, colors tend to overlap because of two or more coloring layers overlapping one another, or gaps may be found in the outputted light because of gaps that are formed in between the coloring layers. This is a problem in that such overlapped colors and gaps yield a display with poor contrast, not only in the case of a reflective display, but also in the case of a transmissive display as well. Also in the liquid crystal device disclosed in Japanese Laid-Open Patent Application Publication 10-186347, since an exposed reflective film is placed inside the black mask, in other words since the exposed reflective film is placed in a region that is separate from the black mask, the available areas for the coloring elements are reduced.
In view of the above, it will be apparent to those skilled in the art from this disclosure that there exists a need for an improved color filter substrate having high visibility, a method of manufacturing such color filter substrate, a displaying device having such color filter substrate, an electro-optical device having such color filter substrate and an electronic instrument having such color filter substrate, that overcome the problems of the conventional art. This invention addresses this need in the art as well as other needs, which will become apparent to those skilled in the art from this disclosure.